(1) Field of the Invention
The present invention relates generally to a solar oven having a multiple zone concentrator and a diffuse focal zone and, more particularly, to a solar oven having a multiple zone concentrator including a booster and a diffuse focal zone.
(2) Description of the Prior Art
Solar energy has been used from the beginning of time for heating. In time, man learned that by concentrating solar energy higher temperatures could be achieved. During the energy shortage of the 1970""s in the United States, many resources were used to develop different types of solar concentrating devices. Some of the developed devices, although effective, required complicated technology to track the sun throughout the day or to convert and transmit the concentrated solar energy for use. Technical precision and instrumentation made such solar devices expensive and difficult to manufacture and maintain.
Solar concentrators as ovens for cooking are known. However, technical precision, instrumentation, and complex materials for such solar concentrators have prevented the ovens from being readily available to the general population. Most had sharp focal zones. Many were sized to collect an inadequate amount of energy, particularly for cooking a reasonable amount of food in a reasonable amount of time. An operator for such solar concentrators as ovens typically should have an advanced understanding of engineering and technology. That is to say, such solar concentrators as ovens are not user friendly.
Thus, there remains a need for a new and improved solar oven having a multiple zone concentrator and a diffuse focal zone. Such a solar oven preferably is robust and simple to manufacture and maintain, while at the same time the inclusion of a booster on such a solar oven would further contribute to the oven""s flexibility.
The present invention is directed to a solar oven that includes a multiple zone concentrator and a diffuse focal zone. The solar oven may include at least one element of symmetry. In such a case, the diffuse focal zone substantially aligns with the oven symmetry element. The diffuse focal zone may include a central region and a peripheral region. The multiple zone concentrator has at least one reflective member for directing radiation to various portions of the diffuse reflective zone. The reflective member has a first reflective zone and a second reflective zone. The first reflective zone may include at least one of a zonal element of symmetry offset from the oven symmetry element. Also, the first reflective zone has a profile that captures and directs radiation to at least a portion of the peripheral region of the diffuse focal zone. The second reflective zone is adjacent to a first end of the first reflective zone and has a profile that captures and directs radiation to at least a portion of the central region of the diffuse focal zone. A receptor support is provided for supporting a receptor substantially within the diffuse focal zone. Optionally, a booster adjacent a distal end of the first reflective zone is provided for directing additional radiation to at least one of the peripheral region and the central region of the various portions of the diffuse focal zone.
In a preferred embodiment, the booster has a straight-line profile. The straight line profile may create an angle from about 2 degrees to about 25 degrees with a tangent to a profile of the first reflective zone at its distal end. A ratio of a length of the booster profile and an aperture length of the at least one reflective member may be about 0.1 to about 0.6. An aperture angle of the at least one reflective member is preferably about 40 degrees to about 120 degrees.
Preferably, the solar oven includes a frame for supporting the at least one reflective member. The solar oven may further include an alignment device for aligning the solar oven with a radiation source. In a preferred embodiment, the alignment device includes a rod substantially parallel to the oven symmetry element and a flat surface substantially perpendicular to the oven symmetry element. A portion of the frame and the at least one reflective member may be integral. Alternatively, the frame and the at least one reflective member are separate. Preferably, the frame includes a base.
In use, a receptor is juxtaposed to the receptor support. The receptor may include at least one absorber such as a coating or finish or both. One coating may be paint. Another coating may be carbon black. Yet another coating may be an anodized coating.
In a preferred embodiment, the at least one absorber and the receptor are integral. The receptor may be at least one of a metal, a ceramic, or a glass. The metal may be at least one of cast iron, steel, aluminum and stainless steel.
In a preferred embodiment, the receptor is cookware. Such cookware may include at least one of a pot, a pan and a sheet.
The receptor support may provide structural reinforcement to the multiple zone concentrator. Also, the receptor support may further include a leveling mechanism such as a universal joint-type.
A thermal insulator may be placed between the receptor and the receptor support. In an embodiment, the insulator stabilizes the receptor. The thermal insulator may be at least one of a polymer, a ceramic or a natural insulating material. For example, abundantly available inexpensive materials such as fiberglass may be preferred.
As stated above, the diffuse focal zone may include a central region and a peripheral region. In a preferred embodiment, the central region is substantially horizontal and the peripheral region is substantially vertical.
In a preferred embodiment, the first reflective zone has a profile that is a conic section such as at least one of a parabola, an ellipse or a hyperbola. More preferably, the conic section is a parabola. A preferred profile of the second reflective zone substantially resembles a portion of a cardioid.
The reflective member is made using a reflective material such as a polished metal that may further include a coating for protecting the polished metal. Preferably, the polished metal is aluminum. Alternatively, the reflective material is a coated polymer. When the reflective material is coated polymer, it is preferably metalized.
As discussed, the solar oven may include at least one element of symmetry and the first reflective zone may include at least one zonal element of symmetry offset from the oven symmetry element. The oven symmetry element may include one of a plane of symmetry and an axis of symmetry. The zonal symmetry element also may include one of a plane of symmetry and an axis of symmetry. Preferably, when the oven symmetry element is a plane of symmetry, the zonal symmetry element also is a plane. Likewise, when the oven symmetry element is an axis of symmetry the zonal symmetry element also is an axis.
Accordingly, one aspect of the present invention is to provide a solar oven including a multiple zone concentrator and a diffuse focal zone. The multiple zone concentrator has at least one reflective member for directing radiation to various portions of the diffuse focal zone. The reflective member has a first reflective zone and a second reflective zone. The first reflective zone has a profile that captures and directs radiation to a first portion of the various portions of the diffuse focal zone. The second reflective zone is adjacent a first end of the first reflective zone. The second reflective zone has a profile that captures and directs radiation to a second portion of the various portions of the diffuse focal zone. A receptor support is provided for supporting a receptor substantially within the diffuse focal zone.
Another aspect of the present invention is to provide a solar oven including at least one of an element of symmetry, a diffuse focal zone or a multiple zone concentrator. The diffuse focal zone is substantially aligned with the oven symmetry element and includes a central region and a peripheral region. The multiple zone concentrator has at least one reflective member for directing radiation to a plurality of portions of the diffuse reflective zone. The reflective member has a first reflective zone and a second reflective zone. The first reflective zone includes at least one of a zonal element of symmetry offset from the oven symmetry element. Also, the first reflective zone has a profile that captures and directs radiation to at least a portion of the peripheral region of the diffuse focal zone. The second reflective zone is adjacent a first end of the first reflective zone. The second reflective zone has a profile that captures and directs radiation to the central region of the diffuse focal zone. A receptor support is provided for supporting a receptor substantially within the diffuse focal zone.
Still another aspect of the present invention is to provide a solar oven including at least one element of symmetry, a multiple zone concentrator and a diffuse focal zone. The diffuse focal zone substantially aligns with the oven symmetry element. The diffuse focal zone includes a central region and a peripheral region. The multiple zone concentrator has at least one reflective member for directing radiation to various portions of the diffuse reflective zone. The reflective member has a first reflective zone and a second reflective zone. The first reflective zone includes at least one of a zonal element of symmetry offset from the oven symmetry element. Also, the first reflective zone has a profile that captures and directs radiation to at least a portion of the peripheral region of the diffuse focal zone. The second reflective zone is adjacent to a first end of the first reflective zone and has a profile that captures and directs radiation to at least a portion of the central region of the diffuse focal zone. A receptor support is provided for supporting a receptor substantially within the diffuse focal zone. Optionally, a booster adjacent a distal end of the first reflective zone is provided for directing additional radiation to at least one of the peripheral region and the central region of various portions of the diffuse focal zone.
Yet another aspect of the present invention is to provide a kit for a solar oven including a multiple zone concentrator and a diffuse focal zone. The multiple zone concentrator has at least one reflective member for directing radiation to various portions of the diffuse focal zone. The reflective member has a first reflective zone and a second reflective zone. The first reflective zone has a profile that captures and directs radiation to a first portion of the various portions of the diffuse focal zone. The second reflective zone is adjacent to a first end of the first reflective zone. The second reflective zone has a profile that captures and directs radiation to a second portion of the various portions of the diffuse focal zone. A receptor support for supporting a receptor substantially within the diffuse focal zone is described. The kit includes a plurality of reflective elements, a template and instructions. Optionally, the kit may include an alignment device for aligning the solar oven with a radiation source. Each reflective element is configurable into at least one portion of at least one reflective member. The template is for configuring the plurality of reflective elements. The instructions provide information for using the template to configuring the plurality of reflective elements to thereby assemble the solar oven.
These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings.